Rain sensor

Abstract

In a rain sensor, a sensor field is arranged between two windshield wiper blades which lie one above the other on a windshield. The sensor field is thus located outside of the field of view of the driver and is wiped by the lower windshield wiper blade. The sensor field is connected to an evaluation circuit arranged on a wiper motor by connecting lines which pass around the lower wiper blade.

We claim: 
     
       1. A rain sensor for a windshield of a vehicle, the vehicle having two windshield wiper blades which, in a position of rest of the two blades, are disposed horizontally in spaced apart relation, one above the other along a surface of the windshield, the sensor comprising: a sensor field disposed on the windshield, a windshield wiper motor which drives the windshield wiper blades, and an evaluation circuit which controls the motor as a function of a signal given off by the sensor field;   wherein the sensor field is arranged at a place between the two windshield wiper blades in their position of rest, and a first one of the wiper blades lies above the sensor field and a second of the wiper blades lies below the sensor field in the position of rest.   
     
     
       2. A rain sensor according to claim 1, wherein the evaluation circuit is operative to provide a sequence of wiping processes wherein, in each of the wiping processes, the motor is activated to drive the two blades with a wiping movement, the evaluation circuit establishing, after each wiping process, a zero point of a signal of the sensor field which leads to a turning off of the wiper motor.   
     
     
       3. A rain sensor according to claim 1, further comprising: connecting lines extending through openings in the windshield for providing electrical connection between the sensor field and the evaluation circuit.   
     
     
       4. A rain sensor according to claim 3, wherein the connecting lines extend laterally from opposite ends of the sensor field around a lower one of the windshield wiper blades and around a lower edge of the windshield. 
     
     
       5. A rains sensor according to claim 1, further comprising connecting lines for electrically connecting the sensor field to the evaluation circuit; and   wherein the connecting lines extend laterally from opposite ends of the sensor field around a lower one of the windshield wiper blades and around a lower edge of the windshield to prevent a shorting of the connecting lines by wetness of one of the wiper blades.   
     
     
       6. A rain sensor according to claim 1, further comprising: connecting lines extending through openings in the windshield for providing electrical connection between the sensor field and the evaluation circuit; and   wherein the connecting lines are spaced away from a path of travel of a lower one of the blades to prevent a shorting of the connecting lines by wetness of one of the wiper blades.